Several parts combine into one character.

試 is a phonetic-semantic compound: 言 (speech, signaling "verbal interrogation") plus 式 (form / pattern / set procedure). The composite picture is asking questions according to a fixed protocol — verifying someone's ability through formal procedure. The character carries two related senses: "to test, to examine" and "to try, to attempt."

Korean reading "si." Top-frequency in education-related vocabulary: 試驗 (siheom, exam / test), 試圖 (sido, attempt), 試食 (sisik, food sampling), 試合 (sihap, sporting match), 入試 (ipsi, entrance exam), 應試 (eungsi, taking an exam). The trinity 入試·試驗·試圖 dominates Korean academic life.

Mandarin shì, 4th tone (simplified 试). Conversational: 试验 (shìyàn, experiment), 试图 (shìtú, to attempt), 考试 (kǎoshì, exam), and the everyday 试穿 (shìchuān, to try on clothes), 试一下 (shì yīxià, "give it a try"). Modern Chinese has elaborated the "try" sense more than the "test" sense.

Japanese on-reading シ powers 試験 (shiken, examination), 試合 (shiai, sporting match), 試食 (shishoku, food sampling). The kun-readings split the two senses cleanly: ためす (tamesu) = "to test something, give it a trial run" — 試してみる (let's try). こころみる (kokoromiru) = "to attempt, to try" — more literary, with the feel of "venture an attempt."

Memory aid: speech (言) following a set form (式) — interrogation by procedure. That's a test.